In thermodynamics and fluid mechanics, compressibility is a measure of the relative volume change of a fluid or solid as a response to a pressure change. In its simple form, the compressibility β may be expressed as β = − 1 V ∂ V ∂ p,where V is volume and p is pressure; the choice to define compressibility as the negative of the fraction makes compressibility positive in the case that an increase in pressure induces a reduction in volume. The specification above is incomplete, because for any object or system the magnitude of the compressibility depends on whether the process is isentropic or isothermal. Accordingly, isothermal compressibility is defined: β T = − 1 V T, where the subscript T indicates that the partial differential is to be taken at constant temperature. Isentropic compressibility is defined: β S = − 1 V S, where S is entropy. For a solid, the distinction between the two is negligible; the speed of sound is defined in classical mechanics as: c 2 = S where ρ is the density of the material.

It follows, by replacing partial derivatives, that the isentropic compressibility can be expressed as: β S = 1 ρ c 2 The inverse of the compressibility is called the bulk modulus denoted K. The compressibility equation relates the isothermal compressibility to the structure of the liquid; the term "compressibility" is used in thermodynamics to describe the deviance in the thermodynamic properties of a real gas from those expected from an ideal gas. The compressibility factor is defined as Z = p V _ R T where p is the pressure of the gas, T is its temperature, V is its molar volume. In the case of an ideal gas, the compressibility factor Z is equal to unity, the familiar ideal gas law is recovered: p = R T V _ Z can, in general, be either greater or less than unity for a real gas; the deviation from ideal gas behavior tends to become significant near the critical point, or in the case of high pressure or low temperature. In these cases, a generalized compressibility chart or an alternative equation of state better suited to the problem must be utilized to produce accurate results.

A related situation occurs in hypersonic aerodynamics, where dissociation causes an increase in the “notional” molar volume, because a mole of oxygen, as O2, becomes 2 moles of monatomic oxygen and N2 dissociates to 2 N. Since this occurs dynamically as air flows over the aerospace object, it is convenient to alter Z, defined for an initial 30 gram moles of air, rather than track the varying mean molecular weight, millisecond by millisecond; this pressure dependent transition occurs for atmospheric oxygen in the 2,500–4,000 K temperature range, in the 5,000–10,000 K range for nitrogen. In transition regions, where this pressure dependent dissociation is incomplete, both beta and the differential, constant pressure heat capacity increases. For moderate pressures, above 10,000 K ions. Z for the resulting plasma can be computed for a mole of initial air, producing values between 2 and 4 for or singly ionized gas; each dissociation absorbs a great deal of energy in a reversible process and this reduces the thermodynamic temperature of hypersonic gas decelerated near the aerospace object.

Ions or free radicals transported to the object surface by diffusion may release this extra energy if the surface catalyzes the slower recombination process. The isothermal compressibility is related to the isentropic compressibility by the relation, β S = β T − α 2 T ρ c p via Maxwell's relations. More stated, β T β S = γ where γ is the heat capacity ratio. See relations between specific heats for a derivation. Compressibility of ionic liquids and molten salts can be expressed as a sum of the contribution of the ionic lattice and of t

Really Simple Systems

Simple Systems CRM is a Cloud CRM provider, offering CRM systems to small and medium sized companies. The company states its mission as "Everything a small business needs to manage their sales and marketing". Simple Systems CRM was founded in 2004 by John Paterson, former CEO of Zeus Technology and COO of Systems Union, with the public launch in January 2006. Simple Systems CRM has over 17,000 users of its hosted customer relationship management systems. Customers include the Royal Academy, the Red Cross, the NHS and IBM as well as thousands of small and medium sized companies; the company is headquartered in the United Kingdom with an office in Australia. The company has won the Software Satisfaction Awards for the best small business CRM system twice, in 2008 and 2010. In 2011 the company won the Database Marketing Award. In 2014 it was a finalist at CRM Idol. In November 2017 PC Mag listed Really Simple Systems in Best Lead Management Software article. In 2018 the company was a finalist in the Small Businesss Awards for Business Innovation and the DevOps Excellence Awards 2019.

In 2018 the company was listed at # 40 by G2 Crowd. In October 2006 the company's Marketing module was launched offering Campaign Management. Email marketing was added in August 2012. In October 2010 the company launched its Free Edition, a Freemium two user hosted CRM system; the existing product was renamed Enterprise Edition. In May 2013 the company was accredited for entry in the UK Government's GCloud CloudStore catalogue. John Paterson, CEO of Really Simple Systems, was awarded the CRM Idol Citizen of the Year in 2014. In July 2013 Really Simple Systems launched a cross-platform version of its CRM, running seamlessly on desktops, laptops and smartphones. In January 2015 the company upgraded its email marketing to offer a built-in alternative to third party products such as MailChimp and Constant Contact. Version 5, launched in March 2017, offered a new user interface, custom dashboards, help drawers and grid customisation. In September 2017 the company announced its compliance with the European Union's General Data Protection Regulation and its phased roll-out of GDPR compliance features in it email marketing module.

In February 2018 it launched a set of GDPR compliance tools allowing users of its email marketing module to collect consent to digital marketing communications. The company is headquartered in Hampshire in the United Kingdom. In January 2008 the company opened its first overseas office in Australia. There are four Really Simple Systems CRM pricing plans: Free Starter Professional Enterprise The product consists of three modules: Sales Marketing Customer Service & Support Really Simple Systems CRM is delivered as a software as a service application; as from Version 5 the product is written using the LAMP stack. Version 4 and previous versions used Microsoft technology; some JavaScript is used on the client. The current version uses responsive design to deliver cross-platform availability; the applications runs in two geographically dispersed datacentres with automated failover to achieve 99.999% uptime. Simple Systems Capterra Software Reviews G2Crowd Software Reviews

Dominique Daguerre

Dominique Daguerre was a Parisian marchand-mercier, in partnership from 1772 with Simon-Philippe Poirier, an arbiter of taste and the inventor of furniture mounted with Sèvres porcelain plaques. Daguerre commissioned furniture from ébénistes such as Adam Weisweiler, Martin Carlin and Claude-Charles Saunier, menuisiers like Georges Jacob, for whom he would provide designs, for resale to his clients, in the manner of an interior decorator. A series of watercolours that Daguerre sent to Albert, Duke of Sachsen-Teschen, the brother-in-law of Marie Antoinette, refurnishing the castle of Laeken near Brussels, are at the Metropolitan Museum of ArtIn 1778 Daguerre moved to London, retaining partnership with Martin-Eloi Lignereux, who remained in Paris. Daguerre set up premises in Chelsea, he was responsible for furnishing interiors at Carlton House, where his account in 1787 for furniture and furnishings totalled £14,565 13s 6d, at Brighton Pavilion for George, Prince of Wales, 1787-89. Chimneypieces were imported from Paris, to be adjusted by craftsmen in London, according to surviving bills.

At Carlton House, at Woburn Abbey, for Earl Spencer at Althorp Daguerre worked in loose collaboration with the architect Henry Holland, though he emphasized in one Carlton House bill, "son Altesse Royale Seul m'a donné des orders" Similar sets of mahogany chairs by Georges Jacob, with openwork backs in lozenges and circles, are in the Royal Collection and in the Library, at Woburn, where Holland was executing alterations.