Biorefinery

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Biorefinery 

 

Debbie Stabenow visiting the Alpena biorefinery.

A biorefinery is a refinery that converts biomass to energy and other beneficial byproducts (such as chemicals). The International Energy Agency Bioenergy Task 42 defined biorefining as "the sustainable processing of biomass into a spectrum of bio-based products (food, feed, chemicals, materials) and bioenergy (biofuels, power and/or heat)". As refineries, biorefineries can provide multiple chemicals by fractioning an initial raw material (biomass) into multiple intermediates (carbohydrates, proteins, triglycerides) that can be further converted into value-added products. Each refining phase is also referred to as a "cascading phase". The use of biomass as feedstock can provide a benefit by reducing the impacts on the environment, as lower pollutants emissions and reduction in the emissions of hazard products. In addition, biorefineries are intended to achieve the following goals:

1. Supply the current fuels and chemical building blocks
2. Supply new building blocks for the production of novel materials with disruptive characteristics
3. Creation of new jobs, including rural areas
4. Valorization of waste (agricultural, urban, and industrial waste)
5. Achieve the ultimate goal of reducing GHG emissions

Classification of biorefinery systems

Chemical diagram of the activity of a biorefinery

Biorefineries can be classified based in four main features:

1. Platforms: Refers to key intermediates between raw material and final products. The most important intermediates are:
   • Biogas from anaerobic digestion
   • Syngas from gasification
   • Hydrogen from water-gas shift reaction, steam reforming, water electrolysis and fermentation
   • C6 sugars from hydrolysis of sucrose, starch, cellulose and hemicellulose
   • C5 sugars (e.g., xylose, arabinose: C₅H₁₀O₅), from hydrolysis of hemicellulose and food and feed side streams
   • Lignin from the processing of lignocellulosic biomass.
   • Liquid from pyrolysis (pyrolysis oil)
2. Products: Biorefineries can be grouped in two main categories according to the conversion of biomass in a energetic or non-energetic product. In this classification the main market must be identified:
   • Energy-driven biorefinery systems: The main product is a second energy carrier as biofuels, power and heat.
   • Material-driven biorefinery systems: The main product is a biobased product
3. Feedstock: Dedicated feedstocks (Sugar crops, starch crops, lignocellulosic crops, oil-based crops, grasses, marine biomass); and residues (oil-based residues, lignocellulosic residues, organic residues and others)
4. Processes: Conversion process to transform biomass into a final product:
   • Mechanical/physical: The chemical structure of the biomass components is preserved. This operation includes pressing, milling, separation, distillation, among others
   • Biochemical: Processes under low temperature and pressure, using microorganism or enzymes.
   • Chemical processes: The substrate suffer change by the action of an external chemical (e.g., hydrolysis, transesterification, hydrogenation, oxidation, pulping)
   • Thermochemical: Severe conditions are apply to the feedstock (high pressure and high temperature, with or without catalyst).

The aforementioned features are used to classified biorefineries systems according to the following method:

1. Identify the feedstock, the main technologies included in the process, platform, and the final products
2. Draw the scheme of the refinery using the features identified in step 1.
3. Label the refinery system according by citing the number of platforms, products, feedstock, and processes involved
4. Elaborate a table with the features identified, and the source of internal energy demand

Some examples of classifications are:

• C6 sugar platform biorefinery for bioethanol and animal feed from starch crops.
• Syngas platform biorefinery for FT-diesel and phenols from straw
• C6 and C5 sugar and syngas platform biorefinery for bioethanol, FT-diesel and furfural from saw mill residues.

Economic viability of biorefinery systems

(a) Counts of operational, planned and under-construction cellulosic biorefineries with biochemical conversion technology, (b) global distribution of plants and (c) shares of corn, wheat, rice, barley and sugarcane residues as feedstock as of 2015

Techno-economic assessment (TEA) is a methodology to evaluate whether a technology or process is economically attractive. TEA research has been developed to provide information about the performance of the biorefinery concept in diverse production systems as sugarcane mills, biodiesel production, pulp and paper mills, and the treatment of industrial and municipal solids waste.

Bioethanol plants and sugarcane mills are well-established processes where the biorefinery concept can be implemented since sugarcane bagasse is a feasible feedstock to produce fuels and chemicals; lignocellulosic bioethanol (2G) is produced in Brazil in two plants with capacities of 40 and 84 Ml/y (about 0.4% of the production capacity in Brazil). TEA of ethanol production using mild liquefaction of bagasse plus simultaneous saccharification and co-fermentation shows a minimum selling price between 50.38 and 62.72 US cents/L which is comparable with the market price. The production of xylitol, citric acid and glutamic acid from sugarcane lignocellulose (bagasse and harvesting residues), each in combination with electricity have been evaluated; the three biorefinery systems were simulated to be annexed to an existing sugar mill in South Africa. The production of xylitol and glutamic acid has shown economic feasibility with an Internal Rate of Return (IRR) of 12.3% and 31.5%, exceeding the IRR of the base case (10.3%). Likewise, the production of ethanol, lactic acid or methanol and ethanol-lactic acid from sugarcane bagasse have been studied; lactic acid demonstrated to be economically attractive by showing the greatest net present value (M$476–1278); in the same way; the production of ethanol and lactic acid as co-product was found to be a favorable scenario (net present value between M$165 and M$718) since this acid has applications in the pharmaceutical, cosmetic, chemical and food industry.

As for biodiesel production, this industry also has the potential to integrate biorefinery systems to convert residual biomasses and wastes into biofuel, heat, electricity and bio-based green products. Glycerol is the main co-product in biodiesel production and can be transformed into valuable products through chemocatalytic technologies; the valorization of glycerol for the production of lactic acid, acrylic acid, allyl alcohol, propanediols, and glycerol carbonate has been evaluated; all glycerol valorization routes shown to be profitable, being the most attractive the manufacture of glycerol carbonate. Palm empty fruit bunches (EFB) are an abundant lignocellulosic residues from the palm oil/biodiesel industry, the conversion of this residue into ethanol, heat and power, and cattle feed were evaluated according to techno-economic principles, the scenarios under study shown reduced economic benefits, although their implementation represented a reduction in the environmental impact (climate change and fossil fuel depletion) compared to the traditional biodiesel production. The economic feasibility for bio-oil production from EFB via fast pyrolysis using the fluidized-bed was studied, crude bio-oil can potentially be produced from EFB at a product value of 0.47 $/kg with a payback period and return on investment of 3.2 years and 21.9%, respectively. The integration of microalgae and Jatropha as a viable route for the production of biofuels and biochemicals has been analyzed in the United Arab Emirates (UAE) context. Three scenarios were examined; in all of them, biodiesel and glycerol is produced; in the first scenario biogas and organic fertilizer is produced by anaerobic fermentation of Jatropha fruit cake and seedcake; the second scenario includes the production of lipids from jatropha and microalgae to produce biodiesel and the production of animal feed, biogas and organic fertilizer; the third scenario involves the production of lipids from microalgae for the production of biodiesel as well as hydrogen and animal feed as final product; only the first scenario was profitable.

In regard to the pulp and paper industry; lignin is a natural polymer co-generated and is generally used as boiler fuel to generate heat or steam to cover the energy demand in the process. Since lignin accounts for 10–30 wt% of the available lignocellulosic biomass and is equivalent to ~40% of its energy contents; the economics of biorefineries depend on the cost-effective processes to transform lignin into value-added fuels and chemicals. The conversion of an existing Swedish kraft pulp mill to the production of dissolving pulp, electricity, lignin, and hemicellulose has been studied; self-sufficiency in terms of steam and the production of excess steam was a key factor for the integration of a lignin separation plant; in this case; the digester has to be upgraded for preserving the same production level and represents 70% of the total investment cost of conversion. The potential of using the kraft process for producing bioethanol from softwoods in a repurposed or co-located kraft mill has been studied, a sugar recovery higher than 60% enables the process to be competitive for the production of ethanol from softwood. The repurposing of a kraft pulp mill to produce both Ethanol and dimethyl-ether has been investigated; in the process, cellulose is separated by and an alkaline pretreatment and then is hydrolyzed and fermented to produce ethanol, while the resulting liquor containing dissolved lignin is gasified and refined to dimethyl ether; the process demonstrate to be self-sufficient in terms of hot utility (fresh steam) demand but with a deficit of electricity; the process can be feasible, economically speaking, but is highly dependent on the development of biofuel prices. The exergetic and economic evaluation for the production of catechol from lignin was performed to determine its feasibility; the results showed that the total capital investment was 4.9 M$ based on the plant capacity of 2,544 kg/d of feedstock; besides, the catechol price was estimated to be 1,100 $/t and the valorization ratio was found to be 3.02.

The high generation of waste biomass is an attractive source for conversion to valuable products, several biorefinery routes has been proposed to upgrade waste streams in valuable products. The production of biogas from banana peel (Musa paradisiaca) under the biorefinery concept is a promissory alternative since is possible to obtain biogas and other co-products including ethanol, xylitol, syngas, and electricity; this process also provides high profitability for high production scales. The economic assessment of the integration of organic waste anaerobic digestion with other mixed culture anaerobic fermentation technologies was studied; the highest profit is obtained by dark fermentation of food waste with separation and purification of acetic and butyric acids (47 USD/t of foodwaste). The technical feasibility, profitability and extent of investment risk to produce sugar syrups from food and beverage waste was analyzed; the returns on investment shown to be satisfactory for the production of fructose syrup (9.4%), HFS42 (22.8%) and glucose-rich syrup (58.9%); the sugar syrups also have high cost competitiveness with relatively low net production costs and minimum selling prices. The valorization of municipal solid waste through integrated mechanical biological chemical treatment (MBCT) systems for the production of levulinic acid has been studied, the revenue from resource recovery and product generation (without the inclusion of gate fees) is more than enough to out- weigh the waste collection fees, annual capital and operating costs.

Environmental impact of biorefinery systems

One of the main goals of biorefineries is to contribute to a more sustainable industry by the conservation of resources and by reducing greenhouse gas emissions and other pollutants. Nevertheless; other environmental impacts may be associated to the production of biobased products; as land use change, eutrophication of water, the pollution of the environment with pesticides, or higher energy and material demand that lead to environmental burdens. Life cycle assessment (LCA) is a methodology to evaluate the environmental load of a process, from the extraction of raw materials to the end use. LCA can be used to investigate the potential benefits of biorefinery systems; multiple LCA studies has been developed to analyse whether biorefineries are more environmentally friendly compared to conventional alternatives.

Feedstock is one of the main sources of environmental impacts in the biofuel production, the source of this impacts are related to the field operation to grow, handle and transport the biomass to the biorefinery gate. Agricultural residues are the feedstock with the lowest environmental impact followed by lignocellulosic crops; and finally by first-generation arable crops, although the environmental impacts are sensitive to factors such as crop management practices, harvesting systems, and crop yields. The production of chemicals from biomass feedstock has shown environmental benefits; bulk chemicals from biomass-derived feedstocks have been studied showing savings on non renewable energy use and greenhouse gas emissions.

The environmental assessment for 1G and 2G ethanol shows that these two biorefinery systems are able to mitigate climate change impacts in comparison to gasoline, but higher climate change benefits are achieved with 2G ethanol production (up to 80% reduction). The conversion of palm empty fruit bunches into valuable products (ethanol, heat and power, and cattle feed) reduces the impact for climate change and fossil fuel depletion compared to the traditional biodiesel production; but the benefits for toxicity and eutrophication are limited. Propionic acid produced by fermentation of glycerol leads to significant reduction of GHG emissions compared to fossil fuel alternatives; however the energy input is double and the contribution to eutrophication is significantly higher The LCA for the integration of butanol from prehydrolysate in a Canadian Kraft dissolving pulp mill shows that the carbon footprint of this butanol may be 5% lower compare to gasoline; but is not as low as corn butanol (23% lower than that of gasoline).

The majority of the LCA studies for the valorization of food waste have been focused on the environmental impacts on biogas or energy production, with only few on the synthesis of high value-added chemicals; hydroxymethylfurfural (HMF) has been listed as one of the top 10 bio-based chemicals by the US Department of Energy; the LCA of eight food waste valorization routes for the production of HMF shows that the most environmentally favorable option uses less polluting catalyst (AlCl3) and co-solvent (acetone), and provides the highest yield of HMF (27.9 Cmol%), metal depletion and toxicity impacts (marine ecotoxicity, freshwater toxicity, and human toxicity) were the categories with the highest values.

Biorefinery in the pulp and paper industry

The pulp and paper industry is considered as the first industrialized biorefinery system; in this industrial process other co-products are produced including tall oil, rosin, vanillin, and lignosulfonates. Apart from these co-products; the system includes energy generation (in for of steam and electricity) to cover its internal energy demand; and it has the potential to feed heat and electricity to the grid.

This industry has consolidated as the highest consumer of biomass; and uses not only wood as feedstock, it is capable of processing agricultural waste as bagasse, rice straw and corn stover. Other important features of this industry are a well-established logistic for biomass production, avoiding competition with food production for fertile land, and presenting higher biomass yields.

Examples

The fully operational Blue Marble Energy company has multiple biorefineries located in Odessa, WA and Missoula, MT.

Canada's first Integrated Biorefinery, developed on anaerobic digestion technology by Himark BioGas is located in Alberta. The biorefinery utilizes Source Separated Organics from the metro Edmonton region, open pen feedlot manure, and food processing waste.

Chemrec's technology for black liquor gasification and production of second-generation biofuels such as biomethanol or BioDME is integrated with a host pulp mill and utilizes a major sulfate or sulfite process waste product as feedstock.

Novamont has converted old petrochemical factories into biorefineries, producing protein, plastics, animal feed, lubricants, herbicides and elastomers from cardoon.

C16 Biosciences produces synthetic palm oil from carbon-containing waste (i.e. food waste, glycerol) by means of yeast.

MacroCascade aims to refine seaweed into food and fodder, and then products for healthcare, cosmetics, and fine chemicals industries. The side streams will be used for the production of fertilizer and biogas. Other seaweed biorefinery projects include MacroAlgaeBiorefinery (MAB4), SeaRefinery and SEAFARM.

FUMI Ingredients produces foaming agents, heat-set gels and emulsifiers from micro-algae with the help of micro-organisms such as brewer's yeast and baker's yeast.

The BIOCON platform is researching the processing of wood into various products. More precisely, their researchers are looking at transforming lignin and cellulose into various products. Lignin for example can be transformed into phenolic components which can be used to make glue, plastics and agricultural products (e.g. crop protection). Cellulose can be transformed into clothes and packaging.

In South Africa, Numbitrax LLC bought a Blume Biorefinery system for producing bioethanol as well as additional high-return offtake products from local and readily available resources such as the prickly pear cactus.

Circular Organics (part of Kempen Insect Valley) grows black soldier fly larvae on waste from the agricultural and food industry (i.e. fruit and vegetable surplus, remaining waste from fruit juice and jam production). These larvae are used to produce protein, grease, and chitin. The grease is usable in the pharmaceutical industry (cosmetics, surfactants for shower gel), replacing other vegetable oils such as palm oil, or it can be used in fodder.

Biteback Insect makes insect cooking oil, insect butter, fatty alcohols, insect frass protein and chitin from superworm (Zophobas morio).

Extragalactic cosmic ray

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Extragalactic_cosmic_ray 

 

The energy spectrum for cosmic rays.

Extragalactic cosmic rays are very-high-energy particles that flow into the Solar System from beyond the Milky Way galaxy. While at low energies, the majority of cosmic rays originate within the Galaxy (such as from supernova remnants), at high energies the cosmic ray spectrum is dominated by these extragalactic cosmic rays. The exact energy at which the transition from galactic to extragalactic cosmic rays occurs is not clear, but it is in the range 10¹⁷ to 10¹⁸ eV.

Observation

Main article: Cosmic Ray Observatory

 

A 3D simulation of the air shower created by a 1 TeV proton hitting the atmosphere, from the COSMUS group at the University of Chicago. The ground shown is an 8 km x 8 km area.

The observation of extragalactic cosmic rays requires detectors with an extremely large surface area, due to the very limited flux. As a result, extragalactic cosmic rays are generally detected with ground-based observatories, by means of the extensive air showers they create. These ground based observatories can be either surface detectors, which observe the air shower particles which reach the ground, or air fluorescence detectors (also called 'fly's eye' detectors), which observe the fluorescence caused by the interaction of the charged air shower particles with the atmosphere. In either case, the ultimate aim is to find the mass and energy of the primary cosmic ray which created the shower. Surface detectors accomplish this by measuring the density of particles at the ground, while fluorescence detectors do so by measuring the depth of shower maximum (the depth from the top of the atmosphere at which the maximum number of particles are present in the shower). The two currently operating high energy cosmic ray observatories, the Pierre Auger Observatory and the Telescope Array, are hybrid detectors which use both of these methods. This hybrid methodology allows for a full three-dimensional reconstruction of the air shower, and gives much better directional information as well as more accurate determination of the type and energy of the primary cosmic ray than either technique on its own.

Pierre Auger Observatory

Main article: Pierre Auger Observatory

The Pierre Auger Observatory, located in the Mendoza province in Argentina, consists of 1660 surface detectors, each separated by 1.5 km and covering a total area of 3000 km², and 27 fluorescence detectors at 4 different locations overlooking the surface detectors. The observatory has been in operation since 2004, and began operating at full capacity in 2008 once construction was completed. The surface detectors are water Cherenkov detectors, each detector being a tank 3.6 m in diameter. One of the Pierre Auger Observatory's most notable results is the detection of a dipole anisotropy in the arrival directions of cosmic rays with energy greater than 8 x 10¹⁸ eV, which was the first conclusive indication of their extragalactic origin.

Telescope Array

Main article: Telescope Array Project

The Telescope Array is located in the state of Utah in the United States of America, and consists of 507 surface detectors separated by 1.2 km and covering a total area of 700 km², and 3 fluorescence detector stations with 12-14 fluorescence detectors at each station. The Telescope Array was constructed by a collaboration between the teams formerly operating the Akeno Giant Air Shower Array (AGASA), which was a surface detector array in Japan, and the High Resolution Fly's Eye (HiRes), which was an air fluorescence detector also located in Utah. The Telescope Array was initially designed to detect cosmic rays with energy above 10¹⁹ eV, but an extension to the project, the Telescope Array Low Energy extension (TALE) is currently underway and will allow observation of cosmic rays with energies above 3 x 10¹⁶ eV

Spectrum and Composition

Energy spectrum of cosmic rays with energy greater than 2.5 x 10¹⁸ eV from data observed by the Pierre Auger Observatory

Two clear and long-known features of the spectrum of extragalactic cosmic rays are the 'ankle', which is a flattening of the spectrum at around 5 x 10¹⁸ eV, and suppression of the cosmic ray flux at high energies (above about 4 x 10¹⁹ eV). More recently the Pierre Auger Observatory also observed a steepening of the cosmic ray spectrum above the ankle, before the steep cutoff above than 10¹⁹ eV (see figure). The spectrum measured by the Pierre Auger Observatory does not appear to depend on the arrival direction of the cosmic rays. However, there are some discrepancies between the spectrum (specifically the energy at which the suppression of flux occurs) measured by the Pierre Auger Observatory in the Southern hemisphere and the Telescope Array in the Northern hemisphere. It is unclear whether this is the result of an unknown systematic error or a true difference between the cosmic rays arriving at the Northern and Southern hemispheres.

The interpretation of these features of the cosmic ray spectrum depends on the details of the model assumed.Historically the ankle is interpreted as the energy at which the steep Galactic cosmic ray spectrum transitions to a flat extragalactic spectrum. However diffusive shock acceleration in supernova remnants, which is the predominant source of cosmic rays below 10¹⁵ eV, can accelerate protons only up to 3 x 10¹⁵ eV and iron up to 8 x 10¹⁶ eV. Thus there must be an additional source of Galactic cosmic rays up to around 10¹⁸ eV. On the other hand, the 'dip' model assumes that the transition between Galactic and extragalactic cosmic rays occurs at about 10¹⁷ eV. This model assumes that extragalactic cosmic rays are composed purely of protons, and the ankle is interpreted as being due to pair production arising from interactions of cosmic rays with the Cosmic Microwave Background (CMB). This suppresses the cosmic ray flux and thus causes a flattening of the spectrum. Older data, as well as more recent data from the Telescope Array do favour a pure proton composition. However recent Auger data suggests a composition which is dominated by light elements to 2 x 10¹⁸ eV, but becomes increasingly dominated by heavier elements with increasing energy. In this case a source of the protons below 2 x 10¹⁸ eV is needed.

The suppression of flux at high energies is generally assumed to be due to the Greisen–Zatsepin–Kuz'min (GZK) effect in the case of protons, or due to photodisintegration by the CMB (the Gerasimova-Rozental or GR effect) in the case of heavy nuclei. However it could also be because of the nature of the sources, that is because of the maximum energy to which sources can accelerate cosmic rays.

As mentioned above the Telescope Array and the Pierre Auger Observatory give different results for the most likely composition. However the data used to infer composition from these two observatories is consistent once all systematic effects are taken into account. The composition of extragalactic cosmic rays is thus still ambiguous

Origin

Unlike solar or galactic cosmic rays, little is known about the origins of extragalactic cosmic rays. This is largely due to a lack of statistics: only about 1 extragalactic cosmic ray particle per square kilometer per year reaches the Earth's surface (see figure). The possible sources of these cosmic rays must satisfy the Hillas criterion,

${\displaystyle E=qBR}$

where E is the energy of the particle, q its electric charge, B is the magnetic field in the source and R the size of the source. This criterion comes from the fact that for a particle to be accelerated to a given energy, its Larmor radius must be less than the size of the accelerating region. Once the Larmor radius of the particle is greater than the size of the accelerating region, it escapes and does not gain any more energy. As a consequence of this, heavier nuclei (with a greater number of protons), if present, can be accelerated to higher energies than protons within the same source.

Active galactic nuclei

Image of an active galactic nucleus of the active galaxy M87.

Active galactic nuclei (AGNs) are well known to be some of the most energetic objects in the universe, and are therefore often considered as candidates for the production of extragalactic cosmic rays. Given their extremely high luminosity, AGNs can accelerate cosmic rays to the required energies even if only 1/1000 of their energy is used for this acceleration. There is some observational support for this hypothesis. Analysis of cosmic ray measurements with the Pierre Auger Observatory suggests a correlation between the arrival directions of cosmic rays of the highest energies of more than 5×10¹⁹ eV and the positions of nearby active galaxies. In 2017, IceCube detected a high energy neutrino with energy 290 TeV whose direction was consistent with a flaring blazar, TXS 0506-056, which strengthened the case for AGNs as a source of extragalactic cosmic rays. Since high-energy neutrinos are assumed to come from the decay of pions produced by the interaction of correspondingly high-energy protons with the Cosmic Microwave Background (CMB) (photo-pion production), or from the photodisintegration of energetic nuclei, and since neutrinos travel essentially unimpeded through the universe, they can be traced back to the source of high-energy cosmic rays.

Clusters of galaxies

A multiwavelength image of the galaxy cluster Abell 1689, with X-ray (purple) and optical (yellow) data. The diffuse X-ray emission arises from the hot intracluster medium

Galaxy clusters continuously accrete gas and galaxies from filaments of the cosmic web. As the cold gas which is accreted falls into the hot intracluster medium, it gives rise to shocks at the outskirts of the cluster, which could accelerate cosmic rays through the diffusive shock acceleration mechanism. Large scale radio halos and radio relics, which are expected to be due to synchrotron emission from relativistic electrons, show that clusters do host high energy particles. Studies have found that shocks in clusters can accelerate iron nuclei to 10²⁰ eV, which is nearly as much as the most energetic cosmic rays observed by the Pierre Auger Observatory. However if clusters do accelerate protons or nuclei to such high energies, they should also produce gamma ray emission due to the interaction of the high-energy particles with the intracluster medium. This gamma ray emission has not yet been observed, which is difficult to explain.

Gamma ray bursts

Gamma ray bursts (GRBs) were originally proposed as a possible source of extragalactic cosmic rays because the energy required to produce the observed flux of cosmic rays was similar their typical luminosity in γ-rays, and because they could accelerate protons to energies of 10²⁰ eV through diffusive shock acceleration. Long gamma ray bursts (GRBs) are especially interesting as possible sources of extragalactic cosmic rays in light of the evidence for a heavier composition at higher energies. Long GRBs are associated with the death of massive stars, which are well known to produce heavy elements. However in this case many of the heavy nuclei would be photo-disintegrated, leading to considerable neutrino emission also associated with GRBs, which has not been observed. Some studies have suggested that a specific population of GRBs known as low-luminosity GRBs might resolve this, as the lower luminosity would lead to less photo-dissociation and neutrino production. These low luminosity GRBs could also simultaneously account for the observed high-energy neutrinos. However it has also been argued that these low-luminosity GRBs are not energetic enough to be a major source of high energy cosmic rays.

Neutron stars

Neutron stars are formed from the core collapse of massive stars, and as with GRBs can be a source of heavy nuclei. In models with neutron stars - specifically young pulsars or magnetars - as the source of extragalactic cosmic rays, heavy elements (mainly iron) are stripped from the surface of the object by the electric field created by the magnetized neutron star's rapid rotation. This same electric field can accelerate iron nucleii up to 10²⁰ eV. The photodisintegration of the heavy nucleii would produce lighter elements with lower energies, matching the observations of the Pierre Auger Observatory. In this scenario, the cosmic rays accelerated by neutron stars within the Milky Way could fill in the 'transition region' between Galactic cosmic rays produced in supernova remnants, and extragalactic cosmic rays.

Right to sexuality

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Right_to_sexuality 

 

Rights
Theoretical distinctions
Claim rights and liberty rights Individual and group rights Natural rights and legal rights Negative and positive rights
Human rights
Civil and political Economic, social and cultural Three generations
Rights by beneficiary
Accused Animals Children Consumers Creditors Deaf Disabled Elders Farmers Humans Natives Intersex Kings LGBT (Transgender) Men Minorities Parents (Mothers, Fathers) Patients Peasants Plants Prisoners Robots States Students Victims Women Workers Youth
Other groups of rights
Assembly Association Asylum Civil liberties Digital Education Fair trial Food Free migration Health Housing Linguistic Movement Property Reproductive Rest and leisure Self defense Self-determination of people Speech Sexuality Water and sanitation

The right to sexuality incorporates the right to express one's sexuality and to be free from discrimination on the grounds of sexual orientation. Specifically, it relates to the human rights of people of diverse sexual orientations, including lesbian, gay, bisexual and transgender (LGBT) people, and the protection of those rights, although it is equally applicable to heterosexuality. The right to sexuality and freedom from discrimination on the grounds of sexual orientation is based on the universality of human rights and the inalienable nature of rights belonging to every person by virtue of being human.

No right to sexuality exists explicitly in international human rights law; rather, it is found in a number of international human rights instruments including the Universal Declaration of Human Rights, the International Covenant on Civil and Political Rights and the International Covenant on Economic, Social and Cultural Rights.

Definition

The concept of the right to sexuality is difficult to define, as it comprises various rights from within the framework of international human rights law.

Sexual orientation is defined in the Preamble to the Yogyakarta Principles as "each person’s capacity for profound emotional, affectional and sexual attraction to, and intimate and sexual relations with, individuals of a different gender or the same gender or more than one gender".

Freedom from discrimination on the grounds of sexual orientation is found in the Universal Declaration of Human Rights (UDHR) and the International Covenant on Civil and Political Rights (ICCPR).

The UDHR provides for non-discrimination in Article 2, which states that:

Everyone is entitled to all the rights and freedoms set forth in this Declaration, without distinction of any kind, such as race, colour, sex, language, religion, political or other opinion, national or social origin, property, birth or other status. Furthermore, no distinction shall be made on the basis of the political, jurisdictional or international status of the country or territory to which a person belongs, whether it be independent, trust, non-self-governing or under any other limitation of sovereignty.

Sexual orientation can be read into Article 2 as "other status" or alternatively as falling under "sex".

In the ICCPR, Article 2 sets out a similar provision for non-discrimination:

Each State Party to the present Covenant undertakes to respect and to ensure to all individuals within its territory and subject to its jurisdiction the rights recognized in the present Covenant, without distinction of any kind, such as race, colour, sex, language, religion, political or other opinion, national or social origin, property, birth or other status.

In Toonen v Australia the United Nations Human Rights Committee (UNHRC) found that the reference to "sex" in Article 2 of the ICCPR included sexual orientation, thereby making sexual orientation prohibited grounds of distinction in respect of the enjoyment of rights under the ICCPR.

The right to be free from discrimination is the basis of the right to sexuality, but it is closely related to the exercise and protection of other fundamental human rights.

Background

Individuals of diverse sexual orientations have been discriminated against historically and continue to be a "vulnerable" group in society today. Forms of discrimination experienced by people of diverse sexual orientations include the denial of the right to life, the right to work and the right to privacy, non-recognition of personal and family relationships, interference with human dignity, interference with security of the person, violations of the right to be free from torture, discrimination in access to economic, social and cultural rights, including housing, health and education, and pressure to remain silent and invisible.

Seventy-eight countries maintain laws that make same-sex consensual sex between adults a criminal offence, and seven countries (or parts thereof) impose the death penalty for same-sex consensual sex. They are Iran, Saudi Arabia, Yemen, Mauritania, Sudan, the twelve northern states of Nigeria, and the southern parts of Somalia.

The right to sexuality has only relatively recently become the subject of international concern, with the regulation of sexuality traditionally falling within the jurisdiction of the nation state. Today numerous international non-governmental organisations and intergovernmental organisations are engaged in the protection of the rights of people of diverse sexual orientation as it is increasingly recognised that discrimination on grounds of sexual orientation is widespread and an unacceptable violation of human rights.

Acts of violence

Acts of violence against LGBT people are often especially vicious compared to other bias-motivated crimes and include killings, kidnappings, beatings, rape, and psychological violence, including threats, coercion and arbitrary depravations of liberty.

Examples of violent acts against people of diverse sexual orientation are too numerous to account here, and they occur in all parts of the world. A particularly distressing example is the sexual assault and murder of fifteen lesbians in Thailand in March 2012. In that example, two lesbian couples were killed by men who objected to their relationship and who were embarrassed when they were unable to convince the women into heterosexual relationships with themselves.

Often acts of violence against people of diverse sexual orientation are perpetrated by the victim's own family. In a case in Zimbabwe, the multiple rape of a lesbian was organised by her own family in an attempt to "cure" her of homosexuality.

In those cases, as in many other cases of violence against people of diverse sexual orientation, State law enforcement authorities are complicit in human rights abuses for failing to persecute violators of rights.

Breach of the right to privacy

Main article: Right to Privacy

The right to privacy is a protected freedom under the UDHR, and the ICCPR which reflects the "widespread, if not universal, human need to pursue certain activities within an intimate sphere, free of outside interference. The possibility to do so is fundamental to personhood." Intimate relationships, whether between two people of the same sex or of different sexes, are among those activities that are subject to a right of privacy.

It has been successfully argued in a number of cases that criminalization of homosexual relationships is an interference with the right to privacy, including decisions in the European Court of Human Rights and the UNHRC.

The freedom to decide on one's own consensual adult relationships, including the gender of that person, without the interference of the State is a fundamental human right. To prohibit the relationships of people of diverse sexual orientation is a breach of the right to sexuality and the right to privacy.

Freedom of expression, assembly and association

Main articles: Freedom of Speech and Freedom of Assembly

Every person, by virtue of their individual autonomy, is free to express themselves, assemble and join in association with others. Freedom of expression is a protected human right under Article 19 of the UDHR and Article 19 of the ICCPR, as is the right to freedom of assembly under Article 20 of the UDHR and Article 21 of the ICCPR.

LGBT people are discriminated against in respect of their ability to defend and promote their rights. Gay pride marches, peaceful demonstrations and other events promoting LGBT rights are often banned by State governments.

In 2011 gay pride marches were banned in Serbia and another march in Moscow was broken up by police, who arrested thirty leading gay rights activists.

Yogyakarta principles

In 2005, twenty-nine experts undertook the drafting of the Yogyakarta Principles on the Application of International Human Rights Law in relation to Sexual Orientation and Gender Identity. The document was intended to set out experiences of human rights violations against people of diverse sexual orientation and transgender people, the application of international human rights law to those experiences and the nature of obligations on States in respect of those experiences.

The Principles can be broadly categorised into the following:

• Principles 1 to 3 set out the universality of human rights and their application to all persons.
• Principles 4 to 11 address fundamental rights to life, freedom from violence and torture, privacy, access to justice and freedom from arbitrary detention.
• Principles 12 to 18 set out non-discrimination in relation of economic, social and cultural rights, including employment, accommodation, social security, education and health.
• Principles 19 to 21 emphasise the importance of freedom of expression, identity and sexuality, without State interference, including peaceful assembly.
• Principles 22 and 23 set out the right to seek asylum from persecution of based on sexual orientation.
• Principles 24 to 26 set out the right to participate in family and cultural life and public affairs.
• Principle 27 sets out the right to promote and defend human rights without discrimination based on sexual orientation.
• Principles 28 and 29 emphasise the importance of holding those who violate human rights accountable, and ensuring redress for those who face rights violations.

The Yogyakarta Principles is an instrument of soft law and is therefore not binding. But it does provide an important standard for States in their obligation to protect the rights of individuals of diverse sexual orientation.

The United Nations

Main article: Sexual Orientation and Gender Identity at the United Nations

On June 17, 2011 the United Nations Human Rights Council in a Resolution on Human Rights, Sexual Orientation and Gender Identity, adopted by a vote of 23 in favour, 19 against, and 3 abstentions, requested the commission of a study to document discriminatory laws and acts of violence against people based on their sexual orientation and gender identity.

The 2011 Resolution was intended to shed light on how international human rights could be used to prevent acts of violence and discrimination against people of diverse sexual orientation.

On 15 December 2011 the first Report on human rights of LGBT people was released by the Office of the United Nations High Commissioner for Human Rights.

The Report made the following recommendations. In order to prevent such acts of violence occurring, United Nations Member States are recommended to:

• Promptly investigate all reported killings and serious incidents of violence against LGBT people, regardless of whether carried out privately or publicly, by State or non-State actors, ensuring accountability for such violations and the establishment of reporting mechanisms for such incidents.
• Take measures to prevent torture and other forms of cruel, inhuman or degrading treatment, ensure accountability for such violations and establish reporting mechanisms.
• Repeal laws that criminalize homosexuality, same-sex sexual conduct, other criminal laws that detain people based on their sexuality and abolish the death penalty for offences involving consensual sexual relations within same-sex relationships.
• Enact comprehensive anti-discrimination legislation, ensuring that combating discrimination based on sexual orientation is in the mandates of national human rights bodies.
• Ensure that freedom of expression, association and peaceful assembly can be exercised safely without discrimination on sexual orientation or gender identity.
• Implement appropriate training programmes for law enforcement personnel, and support public information campaigns to counter homophobia and transphobia amongst the general public and in schools.
• Facilitate legal recognition of preferred gender of transgender persons.

Further action is yet to be taken by the United Nations, although a proposed declaration on sexual orientation and gender identity was brought before the United Nations General Assembly in 2008. However, that declaration has not been officially adopted by the General Assembly and remains open for signatories.

Cosmological horizon

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Cosmological_horizon

A cosmological horizon is a measure of the distance from which one could possibly retrieve information. This observable constraint is due to various properties of general relativity, the expanding universe, and the physics of Big Bang cosmology. Cosmological horizons set the size and scale of the observable universe. This article explains a number of these horizons.

Particle horizon

Main article: Particle horizon

The particle horizon (also called the cosmological horizon, the comoving horizon, or the cosmic light horizon) is the maximum distance from which light from particles could have traveled to the observer in the age of the universe. It represents the boundary between the observable and the unobservable regions of the universe, so its distance at the present epoch defines the size of the observable universe. Due to the expansion of the universe, it is not simply the age of the universe times the speed of light, as in the Hubble horizon, but rather the speed of light multiplied by the conformal time. The existence, properties, and significance of a cosmological horizon depend on the particular cosmological model.

In terms of comoving distance, the particle horizon is equal to the conformal time that has passed since the Big Bang, times the speed of light. In general, the conformal time at a certain time is given in terms of the scale factor ${\displaystyle a}$ by,

${\displaystyle \eta (t)=\int _{0}^{t}{\frac {dt'}{a(t')}}}$

or

${\displaystyle \eta (a)=\int _{0}^{a}{\frac {1}{a'H(a')}}{\frac {da'}{a'}}}$.

The particle horizon is the boundary between two regions at a point at a given time: one region defined by events that have already been observed by an observer, and the other by events which cannot be observed at that time. It represents the furthest distance from which we can retrieve information from the past, and so defines the observable universe.

Hubble horizon

Main article: Hubble volume

Hubble radius, Hubble sphere (not to be confused with a hubble bubble), Hubble volume, or Hubble horizon is a conceptual horizon defining the boundary between particles that are moving slower and faster than the speed of light relative to an observer at one given time. Note that this does not mean the particle is unobservable; the light from the past is reaching and will continue to reach the observer for a while. Also, more importantly, in the current expansion models, light emitted from the Hubble radius will reach us in a finite amount of time. It is a common misconception that light from the Hubble radius can never reach us. In models assuming decreasing H with time (some cases of Friedmann universe), while particles on the Hubble radius recede from us with the speed of light, the Hubble radius gets larger over time, so light emitted towards us from a particle on the Hubble radius will be inside the Hubble radius some time later. In such models, only light emitted from the cosmic event horizon or further will never reach us in a finite amount of time.

The Hubble velocity of an object is given by Hubble's law,

${\displaystyle v=xH}$.

Replacing ${\displaystyle v}$ with speed of light ${\displaystyle c}$ and solving for proper distance ${\textstyle x}$ we obtain the radius of Hubble sphere as

${\displaystyle r_{\text{HS}}(t)={\frac {c}{H(t)}}}$.

In an ever-accelerating universe, if two particles are separated by a distance greater than the Hubble radius, they cannot talk to each other from now on (as they are now, not as they have been in the past), However, if they are outside of each other's particle horizon, they could have never communicated. Depending on the form of expansion of the universe, they may be able to exchange information in the future. Today,

${\displaystyle r_{\text{HS}}(t_{0})={\frac {c}{H_{0}}}}$,

yielding a Hubble horizon of some 4.1 gigaparsecs. This horizon is not really a physical size, but it is often used as useful length scale as most physical sizes in cosmology can be written in terms of those factors.

One can also define a comoving Hubble horizon by simply dividing the Hubble radius by the scale factor

${\displaystyle r_{{\text{HS}},\mathrm {comoving} }(t)={\frac {c}{a(t)H(t)}}}$.

Event horizon

Main article: Event horizon

The particle horizon differs from the cosmic event horizon, in that the particle horizon represents the largest comoving distance from which light could have reached the observer by a specific time, while the event horizon is the largest comoving distance from which light emitted now can ever reach the observer in the future. The current distance to our cosmic event horizon is about five gigaparsecs (16 billion light-years), well within our observable range given by the particle horizon.

In general, the proper distance to the event horizon at time ${\displaystyle t}$ is given by

${\displaystyle d_{e}(t)=a(t)\int _{t}^{t_{max}}{\frac {cdt'}{a(t')}}}$

where ${\displaystyle t_{max}}$ is the time-coordinate of the end of the universe, which would be infinite in the case of a universe that expands forever.

For our case, assuming that dark energy is due to a cosmological constant Λ, there will be a minimum Hubble parameter H_e and a maximum horizon d_e which is often referred to as the only patricle horizon:

${\displaystyle max(d_{e})={\frac {c}{H_{e}}}={\sqrt {\tfrac {3}{\Lambda }}}={\frac {c}{{\sqrt {\Omega _{\Lambda }}}H_{0}}}=17,55\ Gly}$.

Future horizon

In an accelerating universe, there are events which will be unobservable as ${\displaystyle t\rightarrow \infty }$ as signals from future events become redshifted to arbitrarily long wavelengths in the exponentially expanding de Sitter space. This sets a limit on the farthest distance that we can possibly see as measured in units of proper distance today. Or, more precisely, there are events that are spatially separated for a certain frame of reference happening simultaneously with the event occurring right now for which no signal will ever reach us, even though we can observe events that occurred at the same location in space that happened in the distant past. While we will continue to receive signals from this location in space, even if we wait an infinite amount of time, a signal that left from that location today will never reach us. Additionally, the signals coming from that location will have less and less energy and be less and less frequent until the location, for all practical purposes, becomes unobservable. In a universe that is dominated by dark energy which is undergoing an exponential expansion of the scale factor, all objects that are gravitationally unbound with respect to the Milky Way will become unobservable, in a futuristic version of Kapteyn's universe.

Practical horizons

While not technically "horizons" in the sense of an impossibility for observations due to relativity or cosmological solutions, there are practical horizons which include the optical horizon, set at the surface of last scattering. This is the farthest distance that any photon can freely stream. Similarly, there is a "neutrino horizon" set for the farthest distance a neutrino can freely stream and a gravitational wave horizon at the farthest distance that gravitational waves can freely stream. The latter is predicted to be a direct probe of the end of cosmic inflation.